This application claims priority of the German patent application 100 23 569.7 filed May 15, 2000 and of German patent application 100 45 228.0 filed Sep. 13, 2000, which are incorporated by reference herein.
The application concerns a sleeve for movable eyepiece tubes that are provided in an optical device, in particular in a microscope equipped with a binocular tube.
A displacement of one individual eyepiece tube that is mounted movably in a monocular tube can be ergonomically advantageous, for example, if an optimum viewing height for the particular microscope user is thereby to be established. In the case of microscopes equipped with binocular tubes, on the other hand, it is necessary to shift at least one eyepiece tube laterally in corresponding fashion for adaptation to the optimum interpupillary distance of the particular user. The shifting of an eyepiece or of both eyepieces can be accomplished along a straight line; it is also possible for the shifting to be accomplished on a circular path or along a differently curved path. In each case, a passthrough opening, dimensioned in such a way that the eyepiece can be shifted in at least one direction, must be present as part of the design in the housing part carrying the eyepiece. Design problems arise in this context, in that the internal parts of the microscope modules (eyepiece component, microscope tube, etc.) cannot readily be hermetically sealed, so that after extended use, uncontrolled contamination can occur in the internal region of the optical device.
One-piece and multi-piece linear shifter arrangements for movable eyepieces have become known from the field of microscope design, but they cannot effect exact sealing of the eyepiece housing or the tube, since surface contaminants can be increasingly xe2x80x9cpushed intoxe2x80x9d the housing as the eyepiece positions are repeatedly displaced. A hermetic seal that is impervious to air and moisture cannot be achieved with these known features. Complete cleaning of these parts of the microscope is also not possible, since the individual shifter regions are not entirely accessible to the microscope user.
Other attempts to achieve hermetic protection for optical devices consist, for example, in pulling or slipping a so-called xe2x80x9cdrapexe2x80x9d over the entire device (for example, a surgical microscope). This proposal cannot be applied, however, in the specific region between the eyepiece tube and tube housing.
It is therefore the object of the present invention to eliminate the disadvantages of the known approaches and to achieve hermetic protection for the internal device region between a movably mounted optical component (eyepiece or eyepiece receiving tube) and a housing component (eyepiece tube or binocular tube) that is associated therewith and is stationary in the working position. A further object of the present invention is to embody the hermetic seal in such a way that external cleaning of the optical device can easily be accomplished, and the risk of inadvertent removal or shifting of the sleeve can reliably be excluded.
According to the present invention, this object is achieved by a sleeve as defined in the appended claims in that it fits in tightly contacting fashion with its eyepiece-side part around the outer wall of the eyepiece tube, and with its housing-side part around the inner wall of the opening in the tube housing provided for the eyepiece tube. It is advantageous in this context that each of the two end regions has at least two contact surfaces that do not lie in a single plane extending perpendicular to the axis of the eyepiece tube. Advantageously, the eyepiece-side part of the sleeve is configured in cross section in the shape of a upper-case L which engages into a circumferential groove provided in the outer wall of the eyepiece tube. The angle of the part that is L-shaped in cross section can be less than 90xc2x0, so that a clearance-free and exactly sealing annular lip rests against the eyepiece tube outer wall. According to a further embodiment of the present invention, the housing-side part can have, in cross section, the shape of an angled upper-case C which rests against the associated opening in the tube housing. It is advantageous in this context if the tube housing is configured, in the contact region of the housing-side part of the sleeve, in stepped fashion in cross section. The sleeve has in its central part at least one salient protrusion zone and at least one narrower waisted zone.
The sleeve according to the present invention is embodied as a one-piece flexible bellows, and is made of an aging-resistant elastomer. According to a preferred embodiment, portions of the sleeve can be configured in such a way that they have different deformation properties. It is possible, for example, for it to be made in its respective end regions from an elastomer material of greater hardness. It is also possible for the sleeve to have a circumferential, ridge-like thickening in the inner region of its protrusion zone. This thickening forms a monolithic physical unit with the overall sleeve. According to a further embodiment of the present invention, the sleeve can have, in the working position, a retaining ring fitted around it in the outer region of its eyepiece-side part.
It is also possible for the sleeve to have, in the lower part of its end region facing toward the housing, several lobe-shaped protuberances for better mechanical engagement behind the tube housing inner wall. It is advantageous if the material of the sleeve is made of electrically conductive elastomer material, for example to allow use in an antistatic binocular microscope. Lastly, it is possible for the sleeve according to the present invention to have in the region of its protrusion zone, in the working position, an insertable resilient expander ring which maintains the dimensional stability of the protrusion zone from the inside.